Rubber compositions comprising high levels of oily substance and the use thereof in golf balls

ABSTRACT

The present invention is directed to golf balls having at least one layer formed from a rubber composition comprising a base rubber and from 5 to 100 parts of an oily substance, by weight per 100 parts of the base rubber. The rubber composition may be present in any one or more of a core layer, a cover layer, or an intermediate layer.

FIELD OF THE INVENTION

The present invention is directed to rubber compositions comprising highlevels of an oily substance, such as plasticizer and/or process oil, andto the use of such compositions in golf balls.

BACKGROUND OF THE INVENTION

Rubber compositions containing high levels of plasticizer are known. Forexample, U.S. Pat. No. 4,429,068 to Nakahira discloses a cured rubberhaving specific physical properties obtained by curing a rubbercomposition comprising 100 parts by weight of a rubber component, 5 to2,000 parts of a factice, and 20 to 2,000 parts of a softening agent.The reference states that the rubber composition can be used in golfball cores.

U.S. Pat. No. 5,776,294 to Nagel discloses a method of providing curableelastomers crosslinked with the aid of metal salts of a, β-ethylenicallyunsaturated carboxylic acids and, optionally an alkyl aminoalkyl phenolvulcanization inhibitor. Examples are given of metal salts of acrylicand methacrylic acids mixed with ethylene propylene diene rubber andhigh levels of Sunpar 2280, a proprietary plasticizer available from SunRefining and Marketing Company, Philadelphia, Pa.

U.S. Pat. No. 6,380,291 to von Hellens discloses rubber compositionscomprising an acrylate or methacrylate salt, an elastomer curable with aperoxide initiator, and a plasticizer having one or more epoxide groupsper molecule. The reference states that the plasticizer should bepresent in the rubber composition in an amount of from about 2 to about20 phr. The reference also states that golf balls are a typical end use.

In the golf ball industry, rubber compositions containing high levels ofplasticizer are known to be useful as the inner core layer material inthread wound golf balls. For example, U.S. Pat. Nos. 6,593,443 and6,669,581 to Iwami and U.S. Pat. No. 6,846,247 to Kato disclose a woundgolf ball, wherein the inner core layer is preferably obtained byvulcanizing and molding a rubber composition containing an oilysubstance, such as a petroleum compounding oil, a plasticizer, a rubbersubstitute (factice), alkylbenzene, and liquid rubber. The referencesstate that the oily substance is preferably contained in the base rubberin an amount of about 30 to 500 parts, based on 100 parts of the baserubber.

A desire remains for novel rubber compositions containing high levels ofan oily substance, which are useful in solid golf ball applications.Such compositions may provide one or more of the following propertiesrelative to previously known golf ball materials: low cost, ease ofprocessing, reduced compression, and reduced velocity. The presentinvention describes such compositions and their use in a variety of golfball core, cover, and intermediate layers.

SUMMARY OF THE INVENTION

In one embodiment, the present invention provides a solid golf ballcomprising a core and a cover. The core has a diameter of 1.4 inches orless and is formed from a rubber composition comprising a base rubberand from 5 to 100 parts of an oily substance, by weight per 100 parts ofthe base rubber. The cover has an overall thickness of 0.1 inches orgreater.

In another embodiment, the present invention provides a solid golf ballcomprising a rubber core, a polyurethane or polyurea outer cover layer,and an intermediate layer disposed between the core and the outer coverlayer. The core has a diameter of 1.4 inches or less and is formed froma rubber composition comprising a base rubber and from 5 to 100 parts ofan oily substance, by weight per 100 parts of the base rubber. Theintermediate layer has a thickness of 0.1 inches or greater and isformed from a highly resilient material selected from partially- andfully-neutralized acid copolymers and blends thereof.

DETAILED DESCRIPTION OF THE INVENTION

Conventional golf balls can be divided into two general classes: solidand wound. Solid golf balls include one-piece, two-piece (i.e., solidcore and a cover), and multi-layer (i.e., solid core of one or morelayers and/or a cover of one or more layers) golf balls. Wound golfballs typically include a solid, hollow, or fluid-filled center,surrounded by a tensioned elastomeric material, and a cover.

Golf balls of the present invention are solid golf balls having avariety of core structures, intermediate layers, covers, and coatings.Golf ball cores of the present invention may consist of a single,unitary layer, comprising the entire core from the center of the core toits outer periphery, or they may consist of a center surrounded by atleast one outer core layer. Golf ball covers of the present inventionmay also contain one or more layers, such as a double cover having aninner and outer cover layer. Optionally, additional layers may bedisposed between the core and the cover.

Golf balls of the present invention have at least one layer which isformed from a rubber composition of the present invention. The layercomprising the rubber composition may be any one or more layers selectedfrom an inner core layer, an intermediate core layer, an outer corelayer, an inner cover layer, an intermediate cover layer, an outer coverlayer, or an intermediate layer disposed between a core and a cover. Ina particular embodiment, the rubber composition comprises all or part ofthe core layer of a two-piece golf ball. In another particularembodiment, the rubber composition comprises all or part of the innercore layer and/or outer core layer of a multi-layer golf ball. In yetanother embodiment, the rubber composition comprises all or part of theinner cover layer of a multi-layer ball.

Rubber Composition

Rubber compositions of the present invention include a base rubber and ahigh level of an oily substance. For purposes of the present invention,a composition contains “a high level of an oily substance” if the oilysubstance is present in the composition in an amount of 2 parts orgreater by weight per 100 parts of base rubber. In a particularembodiment, the oily substance is present in the composition in anamount of 2.5 parts or greater, or 5 parts or greater, by weight per 100parts of base rubber. In another particular embodiment, the oilysubstance is present in the composition in an amount within the rangehaving a lower limit of 2 parts, or 2.5 parts, or 3 parts, or 5 parts,or 10 parts, by weight per 100 parts of rubber, and an upper limit of 20parts, or 25 parts, or 30 parts, or 50 parts, or 100 parts, or 200parts, by weight per 100 parts of rubber. In another particularembodiment, the oily substance is present in the composition in anamount within the range having a lower limit of 10 parts, or 15 parts,or 20 parts, or 25 parts, by weight per 100 parts of rubber, and anupper limit of 100 parts, or 200 parts, by weight per 100 parts orrubber.

The oily substance is generally selected from rubber processing oils,vegetable oils, vulcanized vegetable oils, animal oils, liquid rubbers,plasticizers, and combinations thereof. Suitable rubber processing oilsinclude, for example, aromatic oils, naphthenic oils, and paraffinicoils, as classified by ASTM D2226. In a particular embodiment, the oilysubstance is selected from paraffinic oil, naphthenic oil, andcombinations thereof. Particularly suitable paraffinic and naphthenicoils include, for example, Sunpar® paraffinic oil, commerciallyavailable from Sunoco, Inc. of Philadelphia, Pa.; Paralux® paraffinicoil, commercially available from Chevron Corporation of San Ramon,Calif.; and Unithene naphthenic oil, commercially available from Ergon,Inc. of Jackson, Miss. Suitable vegetable oils include, for example,rapeseed, castor, linseed, soybean, and tung oil. Suitable vulcanizedvegetable oils include, for example, semi-translucent factice, blackfactice, and brown factice; in particular, “F14” and “F17” sulfurvulcanized rapeseed oils, “K14D” sulfur vulcanized modified fatty acids,“Gloria 17” sulfur vulcanized rapeseed oil, “Hamburg 4” partiallyhydrogenated rapeseed oil, and “WP” peroxide crosslinked modified castoroil free of sulfur and chlorine, all of which are commercially availablefrom RT Vanderbilt Company, Inc. of Norwalk, Conn. Suitable animal oilsinclude, for example, whale oil and fish oil. Suitable liquid rubbersinclude, for example, liquid polybutadiene and liquid polyisoprene.Suitable plasticizers include, for example, adipates, e.g., dioctyladipate, diisopropyl adipate, dibutyl adipate, bis(2-ethylhexyl)adipate,polypropylene adipate, diisodecyl adipate, bis(2-methylhexyl)adipate,dicapryl adipate, and octyldecyl adipate; phthalates, e.g., dioctylphthalate, dibutyl phthalate, nonyl phthalate, butylbenzyl phthalate,diheptyl phthalate, dihexyl phthalate, dinonyl phthalate, ditridecylphthalate, dicapryl phthalate, dilauryl phthalate, diisodecyl phthalate,dimethylglycol phthalate, butyl octyl phthalate, dicyclohexyl phthalate,butyl cyclohexyl phthalate, butyl lauryl phthalate, butylcoconutalkylphthalate, octyldecanoyl phthalate, octyldecyl phthalate,bis(2-ethylhexyl)phthalate, bis(3,5,5-trimethylhexyl) phthalate,bis(diethyleneglycolmonomethylether) phthalate, butyl benzyl phthalate,and texanol benzyl phthalatic; phosphates, e.g., tricresyl phosphate,trimethyl phosphate, triethyl phosphate, isopropylated triphenylphosphate, tributyl phosphate, trioctyl phosphate, tri-2-ethyl hexylphosphate, tributoxy phosphate, triphenyl phosphate, trixylenylphosphate, 2-ethylhexyl diphenyl phosphate, tris(2,6-dimethylphenyl)phosphate, isodecyl diphenyl phosphate, mixed dodecyl andtetradecyl diphenyl phosphate, butylphenyl diphenyl phosphate, xylenyldiphenyl phosphate, phenyl dicresyl phosphate, xylenyl dicresylphosphate, cresyl diphenyl phosphate, cresyl dixylenyl phosphate,diphenyl phosphate hydroquinone condensate, trichloroethyl phosphate,tri(β-chloropropyl)phosphate, tri(dichloropropyl)phosphate, andtri(tribromoneopentyl)phosphate; sebacates, e.g., dioctyl sebacate and2-ethyl hexyl sebacate; alkyl benzenes, e.g., 1-dodecyl-4-hexylbenzene,1-dodecyl-3-hexylbenzene, and 1,2,3-hemimellitene; citrates, e.g.,acetyl tributyl citrate, triethyl citrate, acetyl triethyl citrate, andtributyl citrate; glycolic acid esters, e.g., ethylphthalyl ethyleneglycolate, methylphthalyl ethylene glycolate, and butylphthalyl ethyleneglycolate; epoxy compounds, e.g., butylepoxy stearate, octylepoxystearate, epoxybutyl oleate, epoxidized butyl oleate, epoxidized soybeanoil, epoxidized linseed oil, epoxidized alkyl oil, and epoxidized alkyloil alcohol esters, trimellitates, e.g., tri-2-ethyl hexyl trimellitateand tri-octyl trimellitate; fatty acid esters, e.g., butyl oleate;benzoates, e.g., diethylene glycol dibenzoate and dipropylene glycoldibenzoate; azelates; glutarates; alkyl alcohols; and combinationsthereof. Suitable plasticizers also include those disclosed in U.S.Patent Application Publication No. 2005/0137030, the entire disclosureof which is hereby incorporated herein by reference.

The base rubber is generally selected from polybutadiene rubber,polyisoprene rubber, natural rubber, ethylene propylene rubber, ethylenepropylene diene rubber, styrene-butadiene rubber, and combinations oftwo or more thereof. A preferred base rubber is one or morepolybutadiene(s). Particularly suitable polybutadiene blends aredisclosed, for example, in U.S. Pat. No. 6,774,187, the entiredisclosure of which is hereby incorporated herein by reference. Anotherpreferred base rubber is one or more polybutadiene(s) optionally mixedwith one or more elastomer(s) selected from polyisoprene rubber, naturalrubber, ethylene propylene rubber, ethylene propylene diene rubber,styrene-butadiene rubber, polystyrene elastomers, polyethyleneelastomers, polyurethane elastomers, polyurea elastomers,metallocene-catalyzed elastomers, and plastomers. When the rubbercomposition contains an additional elastomer (i.e., in addition to thebase rubber), the additional elastomer is present in the rubbercomposition in an amount of less than 100 parts by weight per 100 partsof the base rubber. In a particular embodiment, the additional elastomeris present in an amount of 50 parts or less, or 45 parts or less, or 20parts or less, or 5 parts or less, by weight per 100 parts of the baserubber.

The base rubber is typically cured using a conventional curing process.Suitable curing processes include, for example, peroxide curing, sulfurcuring, radiation, and combinations thereof. In one embodiment, the baserubber is peroxide cured. Organic peroxides suitable as free radicalinitiators include, for example, dicumyl peroxide;n-butyl-4,4-di(t-butylperoxy) valerate;1,1-di(t-butylperoxy)3,3,5-trimethylcyclohexane;2,5-dimethyl-2,5-di(t-butylperoxy) hexane; di-t-butyl peroxide;di-t-amyl peroxide; t-butyl peroxide; t-butyl cumyl peroxide;2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3;di(2-t-butyl-peroxyisopropyl)benzene; dilauroyl peroxide; dibenzoylperoxide; t-butyl hydroperoxide; and combinations thereof. Peroxide freeradical initiators are generally present in the rubber compositions inan amount within the range having a lower limit of 0.05 parts, or 0.1parts, or 0.25 parts, or 1 part, or 1.5 parts, by weight per 100 partsof the base rubber, and an upper limit of 2.5 parts, or 3 parts, or 5parts, or 6 parts, or parts, or 15 parts, by weight per 100 parts of thebase rubber. Coagents can be used with peroxides to increase the stateof cure. Suitable coagents include, for example, metal salts ofunsaturated carboxylic acids having from 3 to 8 carbon atoms;unsaturated vinyl compounds and polyfunctional monomers (e.g.,trimethylolpropane trimethacrylate); phenylene bismaleimide; andcombinations thereof. Particularly suitable metal salts include, forexample, one or more metal salts of acrylates, diacrylates,methacrylates, and dimethacrylates, wherein the metal is selected frommagnesium, calcium, zinc, aluminum, lithium, and nickel. In a particularembodiment, the coagent is selected from zinc salts of acrylates,diacrylates, methacrylates, and dimethacrylates. In another particularembodiment, the coagent is zinc diacrylate. When the agent is zincdiacrylate and/or zinc dimethacrylate, the coagent is typically includedin the rubber composition in an amount within the range having a lowerlimit of 1 part, or 5 parts, or 10 parts, or 20 parts, by weight per 100parts of the base rubber, and an upper limit of 25 parts, or 30 parts,or 35 parts, or 40 parts, or 50 parts, or 60 parts, by weight per 100parts of the base rubber. When one or more less active coagents areused, such as zinc monomethacrylate and various liquid acrylates andmethacrylates, the amount of less active coagent used may be the same asor higher than for zinc diacrylate and zinc dimethacrylate coagents.

Sulfur and sulfur-based curing agents with optional accelerators may beused in combination with or in replacement of the peroxide initiators tocrosslink the base rubber. Suitable curing agents and acceleratorsinclude, for example, sulfur; N-oxydiethylene 2-benzothiazolesulfenamide; N,N-diorthotolylguanidine; bismuth dimethyldithiocarbamate;N-cyclohexyl 2-benzothiazole sulfenamide; N,N-diphenylguanidine;4-morpholinyl-2-benzothiazole disulfide; dipentamethylenethiuramhexasulfide; thiuram disulfides; mercaptobenzothiazoles; sulfenamides;dithiocarbamates; thiuram sulfides; guanidines; thioureas; xanthates;dithiophosphates; aldehyde-amines; dibenzothiazyl disulfide;tetraethylthiuram disulfide; tetrabutylthiuram disulfide; andcombinations thereof.

High energy radiation sources capable of generating free radicals mayalso be used to crosslink the base rubber. Suitable examples of suchradiation sources include, for example, electron beams, ultra-violetradiation, gamma radiation, X-ray radiation, infrared radiation, heat,and combinations thereof.

Further examples of suitable free radical initiators, coagents, andcuring agents are disclosed in U.S. Patent Application Publication Nos.2004/0214661 and 2003/0144087 and U.S. Pat. Nos. 6,566,483, 6,695,718,and 6,939,907, the entire disclosures of which are hereby incorporatedby reference.

Rubber compositions of the present invention may also contain acis-to-trans conversion compound, such as a halogenated organosulfur,organic disulfide, or inorganic disulfide compound. Particularlysuitable halogenated organosulfur compounds include, but are not limitedto, halogenated thiophenols having the general formula

wherein R₁-R₅ are independently selected from C₁-C₈ alkyl groups,halogen groups, thiol groups (—SH), carboxylated groups, sulfonatedgroups, and hydrogen, in any order, and wherein at least one group ishalogenated. Suitable examples include, but are not limited to,pentafluorothiophenol; 2-fluorothiophenol; 3-fluorothiophenol;4-fluorothiophenol; 2,3-fluorothiophenol; 2,4-fluorothiophenol;3,4-fluorothiophenol; 3,5-fluorothiophenol 2,3,4-fluorothiophenol;3,4,5-fluorothiophenol; 2,3,4,5-tetrafluorothiophenol;2,3,5,6-tetrafluorothiophenol; 4-chlorotetrafluorothiophenol;pentachlorothiophenol; 2-chlorothiophenol; 3-chlorothiophenol;4-chlorothiophenol; 2,3-chlorothiophenol; 2,4-chlorothiophenol;3,4-chlorothiophenol; 3,5-chlorothiophenol; 2,3,4-chlorothiophenol;3,4,5-chlorothiophenol; 2,3,4,5-tetrachlorothiophenol;2,3,5,6-tetrachlorothiophenol; pentabromothiophenol; 2-bromothiophenol;3-bromothiophenol; 4-bromothiophenol; 2,3-bromothiophenol;2,4-bromothiophenol; 3,4-bromothiophenol; 3,5-bromothiophenol;2,3,4-bromothiophenol; 3,4,5-bromothiophenol;2,3,4,5-tetrabromothiophenol; 2,3,5,6-tetrabromothiophenol;pentaiodothiophenol; 2-iodothiophenol; 3-iodothiophenol;4-iodothiophenol; 2,3-iodothiophenol; 2,4-iodothiophenol;3,4-iodothiophenol; 3,5-iodothiophenol; 2,3,4-iodothiophenol;3,4,5-iodothiophenol; 2,3,4,5-tetraiodothiophenol;2,3,5,6-tetraiodothiophenol; and their salts, preferably their zinc ormagnesium salts. Halogenated organosulfur compounds are more fullydisclosed, for example, in U.S. Pat. No. 6,635,716, the entiredisclosure of which is hereby incorporated herein by reference. In aparticular embodiment, the halogenated thiophenol compound ispentachlorothiophenol, which is commercially available in neat form orunder the tradename STRUKTOL®, a clay-based carrier containing thesulfur compound pentachlorothiophenol loaded at 45 percent (correlatingto 2.4 parts PCTP). STRUKTOL® is commercially available from StruktolCompany of America of Stow, Ohio. Pentachlorothiophenol is commerciallyavailable, in neat and salt forms, from eChinachem of San Francisco,Calif. In another particular embodiment, the halogenated thiophenolcompound is the zinc salt of pentachlorothiophenol, also available fromeChinachem of San Francisco, Calif. Suitable cis-to-trans conversioncompounds are more fully described, for example, in U.S. PatentApplication Publication No. 2005/0187353 and U.S. Pat. Nos. 5,252,652,5,697,856, 5,816,944, 6,139,447, 6,184,301, 6,465,578, and 6,525,141,the entire disclosures of which are hereby incorporated herein byreference.

When rubber compositions of the present invention contain a cis-to-transconversion compound, the cis-to-trans conversion compound is generallypresent in the rubber composition in an amount within the range having alower limit of 0.01 parts, or 0.05 parts, or 2.2 parts, or 2.3 parts,per 100 parts of the base rubber, and an upper limit of 4 parts, or 5parts, per 100 parts of the base rubber.

Rubber compositions of the present invention optionally contain one ormore antioxidants. Some antioxidants also act as free radicalscavengers. Thus, when antioxidants are included in the rubbercomposition, the amount of free radical initiator used may be as high orhigher than the amounts disclosed herein.

Rubber compositions of the present invention optionally contain one ormore particulate fillers selected from inorganic fillers, such as zincoxide, titanium dioxide, tin oxide, calcium oxide, magnesium oxide,barium sulfate, zinc sulfate, calcium carbonate, zinc carbonate, bariumcarbonate, mica, talc, clay, silica, lead silicate, and the like; highspecific gravity metal powder fillers, such as tungsten powder,molybdenum powder, and the like; regrind, i.e., core material that isground and recycled; and nano-fillers. The amount of particulatematerial(s) present in rubber compositions of the present invention istypically within the range having a lower limit of 5 parts, or 10 parts,by weight per 100 parts of the base rubber, and an upper limit of 30parts, or 50 parts, or 100 parts, by weight per 100 parts of the baserubber.

Rubber compositions of the present invention optionally contain one ormore additives selected from free radical scavengers, scorch retarders,coloring agents, fluorescent agents, chemical blowing and foamingagents, defoaming agents, stabilizers, softening agents, impactmodifiers, and the like. The amount of additive(s) typically present inrubber compositions of the present invention is typically within therange having a lower limit of 0 parts by weight per 100 parts of thebase rubber and an upper limit of 20 parts, or 50 parts, or 100 parts,or 150 parts, by weight per 100 parts of the base rubber.

Filler materials may be dual-functional fillers, for example, zinc oxide(which may be used as a filler/acid scavenger) and titanium dioxide(which may be used as a filler/brightener material). Further examples ofsuitable fillers and additives include, but are not limited to, thosedisclosed in U.S. Patent Application Publication No. 2003/0225197, theentire disclosure of which is hereby incorporated herein by reference.

The present invention is not limited by any particular method for makingthe rubber composition. In a typical mixing process, the rubbercomposition is formed by combining the materials in a single- ormulti-pass procedure using mixing equipment, such as a Banbury mixer,two-roll mill, etc. The oily substance is optionally preblended ormasterbatched with a polymer prior to combining it with the base rubber.

Rubber compositions of the present invention can be used in a variety ofapplications. For example, rubber compositions of the present inventionare suitable for use in golf equipment, including, but not limited to,golf balls, golf shoes, and golf clubs.

Golf Ball Applications

Golf balls of the present invention are solid balls having one or morecore layer(s), one or more cover layer(s), and optionally one or moreintermediate layer(s) disposed between the core and the cover. At leastone of the layers is formed from a rubber composition comprising highlevels of an oily substance, as described herein. In golf balls havingtwo or more layers which comprise a rubber composition of the presentinvention, the rubber composition of one layer may be the same or adifferent rubber composition as another layer.

Golf balls of the present invention preferably have at least one corelayer formed from a rubber composition of the present invention. In aparticular embodiment, the present invention provides a golf ball havinga single layer core formed from a rubber composition of the presentinvention. In another particular embodiment, the present inventionprovides a golf ball comprising a dual core having an inner core layerand an outer core layer, wherein the inner core layer is formed from arubber composition of the present invention. In another particularembodiment, the present invention provides a golf ball comprising a dualcore having an inner core layer and an outer core layer, wherein theouter core layer is formed from a rubber composition of the presentinvention. In another particular embodiment, the present inventionprovides a golf ball comprising a multilayer core having an inner corelayer, an outer core layer, and at least one intermediate core layer,wherein the inner core layer is formed from a rubber composition of thepresent invention. In another particular embodiment, the presentinvention provides a golf ball comprising a multilayer core having aninner core layer, an outer core layer, and at least one intermediatecore layer, wherein the outer core layer is formed from a rubbercomposition of the present invention. In another particular embodiment,the present invention provides a golf ball comprising a multilayer corehaving an inner core layer, an outer core layer, and at least oneintermediate core layer, wherein an intermediate core layer is formedfrom a rubber composition of the present invention.

Golf ball cores of the present invention preferably have an overalldiameter within the range having a lower limit of 0.5 inches or 0.8inches or 1 inch or 1.25 inches or 1.3 inches and an upper limit of 1.35inches or 1.4 inches or 1.5 inches or 1.56 inches or 1.6 inches or 1.63inches. Inner core layers of the present invention preferably have adiameter within the range having a lower limit of 0.5 inches or 0.75inches or 1 inch and an upper limit of 1.25 inches or 1.4 inches or 1.55inches or 1.57 inches or 1.58 inches. Outer core layers of the presentinvention preferably have a thickness within the range having a lowerlimit of 0.01 inches or 0.015 inches or 0.02 inches or 0.025 inches or0.03 inches and an upper limit of 0.05 inches or 0.1 inches or 0.28inches or 0.35 inches or 0.4 inches or 0.5 inches or 0.55 inches. Thetotal thickness of intermediate core layer(s) of the present inventionis preferably within the range having a lower limit of 0.02 inches or0.025 inches or 0.032 inches and an upper limit of 0.15 inches or 0.22inches or 0.28 inches.

Golf ball cores having at least one layer formed from a rubbercomposition of the present invention may have reduced compression and/orreduced velocity due to the presence of the oily substance. Thus, ingolf ball applications requiring high compression and/or high velocity,it may be desirable to include one or more layer(s) formed from a highlyresilient material and/or for the cover to have an overall thickness of0.1 inches or greater. Suitable highly resilient materials include, butare not limited to, the “low deformation” materials disclosed in U.S.Patent Application Publication No. 2005/0250600; thermoplastics withhigh resilience and softness, such as those disclosed in PCT PublicationNo. WO 01/29129 and U.S. Pat. No. 6,653,382; highly-resilientthermoplastic elastomer compositions, such as those disclosed in PCTPublication No. WO 00/23519 and U.S. Pat. No. 6,815,480;highly-neutralized ethylene copolymers, such as those disclosed in U.S.Pat. No. 6,777,472; ionomer resins containing high levels of fatty acidsalts, such as those disclosed in U.S. Pat. No. 5,306,760;highly-neutralized acid polymers, such as those disclosed in U.S. Pat.No. 6,756,436; Na-ionomer/Li-ionomer blends, such as those disclosed inU.S. Patent Application Publication No. 2005/0255941; sulfonated and/orphosphonated ionomer compositions, such as those disclosed in U.S. Pat.No. 6,245,862; stearic modified ionomers, such as those disclosed inU.S. Pat. No. 6,100,321; blends of relatively hard polyamide andrelatively soft ionomer resin, such as those disclosed in U.S. Pat. No.6,187,864; poly(trimethylene terephthalate) compositions, such as thosedisclosed in U.S. Pat. No. 6,232,400; glycidyl polymer compositions,such as those disclosed in U.S. Pat. No. 6,290,611; and acrylateester-containing ionomeric resins, such as those disclosed in U.S. Pat.No. 5,902,855. Each of the above patents and publications is herebyincorporated herein by reference in its entirety. Suitable highlyresilient materials also include any hard, high flexural modulus,resilient material that is compatible with the other materials of thegolf ball, including, for example, thermoplastic and thermosetpolyurethanes, thermoplastic and thermoset polyureas, thermoplastic andthermoset polyetheresters, thermoplastic and thermoset polyetheramides,thermoplastic and thermoset polyesters, dynamically vulcanizedelastomers, functionalized styrene-butadiene elastomers, metallocenepolymers, nylon, and acrylonitrile-butadiene-styrene copolymers, andcombinations of one or more thereof. Also suitable as highly resilientmaterials are Surlyn® ionomers, Hytrel® thermoplastic polyesterelastomers, and ionomeric materials sold under the trade names DuPont®HPF 1000 and DuPont® HPF 2000, all of which are commercially availablefrom E. I. du Pont de Nemours and Company; lotek® ionomers, commerciallyavailable from ExxonMobil Chemical Company; and Pebax® thermoplasticpolyether block amides, commercially available from Arkema Inc.

Golf ball cores may include one or more layers formed from a suitablematerial other than the rubber composition of the present invention.Suitable core materials for the golf balls disclosed herein include, forexample, natural and synthetic rubbers, such as polybutadiene,polyisoprene, ethylene propylene rubber, ethylene propylene dienerubber, styrene-butadiene rubber, styrenic block copolymer rubbers (suchas SI, SIS, SB, SBS, SIBS, and the like, where “S” is styrene, “I” isisobutylene, and “B” is butadiene), butyl rubber, halobutyl rubber,copolymers of isobutylene and para-alkylstyrene, halogenated copolymersof isobutylene and para-alkylstyrene, copolymers of butadiene withacrylonitrile, polychloroprene, alkyl acrylate rubber, chlorinatedisoprene rubber, and acrylonitrile chlorinated isoprene rubber;metallocene polymers; acid copolymers and ionomers; and combinationsthereof.

Golf ball covers of the present invention include single, dual, andmultilayer covers, and preferably have an overall thickness within therange having a lower limit of 0.01 inches or 0.02 inches or 0.05 inchesor 0.06 inches or 0.1 inches or 0.115 inches and an upper limit of 0.15inches or 0.2 inches or 0.25 inches or 0.5 inches or 0.8 inches or 1.0inches. Dual and multilayer covers have an inner cover layer and anouter cover layer, and multilayer covers additionally have at least oneintermediate cover layer disposed between the inner cover layer and theouter cover layer. Inner cover layers of the present inventionpreferably have a thickness within the range having a lower limit of0.005 inches or 0.01 inches or 0.02 inches or 0.025 inches or 0.03inches and an upper limit of 0.05 inches or 0.1 inches or 0.15 inches or0.2 inches. Outer cover layers of the present invention preferably havea thickness of 0.01 inches or 0.02 inches or 0.025 inches or 0.03 inchesand an upper limit of 0.04 inches or 0.05 inches or 0.15 inches or 0.2inches. Intermediate cover layer(s) of the present invention preferablyhave a thickness of 0.01 inches or 0.02 inches or 0.025 inches and anupper limit of 0.05 inches or 0.15 inches or 0.2 inches.

Golf ball covers of the present invention may include one or more layersformed from a suitable material other than a rubber composition of thepresent invention. The cover material is preferably a tough,cut-resistant material, selected based on the desired performancecharacteristics. Suitable cover materials for the golf balls disclosedherein include, for example, the highly resilient materials disclosedabove; polyethylene, including, for example, low density polyethylene,linear low density polyethylene, and high density polyethylene;polypropylene; rubber-toughened olefin polymers; acid copolymers whichdo not become part of an ionomeric copolymer; plastomers; flexomers;block copolymers, such as styrene-butadiene rubber and isoprene- orethylene-butylene rubber; dynamically vulcanized elastomers; ethylenevinyl acetates; ethylene methacrylates; vinyl resins comprising vinylchloride; acrylic resins; polyamides, amide-ester elastomers, and graftcopolymers of ionomer and polyamide, including, for example, Pebax®thermoplastic polyether block amides, commercially available from ArkemaInc; crosslinked transpolyisoprene blends; polyurethanes; polyureas;polyester-based thermoplastic elastomers, such as Hytrel®, commerciallyavailable from E. I. du Pont de Nemours and Company; polyurethane-basedthermoplastic elastomers, such as Elastollan®, commercially availablefrom BASF; polyphenylene oxide resins, such as Noryl®, commerciallyavailable from GE Plastics; synthetic or natural vulcanized rubber;ionomeric resins; and combinations thereof. Suitable cover materials andconstructions also include, but are not limited to, those disclosed inU.S. Pat. Nos. 6,117,025, 6,767,940, and 6,960,630, the entiredisclosures of which are hereby incorporated herein by reference.

Commercially available ionomeric cover materials include, but are notlimited to, Surlyn® ionomer resins and DuPont® HPF 1000 and HPF 2000,commercially available from E. I. du Pont de Nemours and Company; andIotek® ionomers, commercially available from ExxonMobil ChemicalCompany. Also suitable are blends of ionomers with thermoplasticelastomers. Suitable ionomeric cover materials are further disclosed,for example, in U.S. Pat. Nos. 6,653,382, 6,756,436, 6,894,098,6,919,393, and 6,953,820, the entire disclosures of which are herebyincorporated by reference.

Suitable polyurethane cover materials are further disclosed, forexample, in U.S. Pat. No. 6,756,436, the entire disclosure of which ishereby incorporated herein by reference. When used as cover materials,polyurethane and polyurea can be thermoset or thermoplastic. Thermosetmaterials can be formed into golf ball layers by conventional casting orreaction injection molding techniques. Thermoplastic materials can beformed into golf ball layers by conventional compression or injectionmolding techniques. Light stable polyurethanes and polyureas are apreferred material for single layer covers and the outer cover layer ofdual and multilayer covers. High modulus thermoplastics are a preferredmaterial for the inner cover layer of dual and multilayer covers.

Golf ball cover materials optionally contain one or more filler(s)and/or additive(s). Suitable fillers include, for example, metal oxides,barium sulfate, zinc sulfate, calcium carbonate, zinc carbonate, bariumcarbonate, mica, talc, clay, silica, lead silicate, and the like.Suitable additives include, for example, coloring agents, fluorescentagents, whitening agents, metals, antioxidants, dispersants, UVabsorbers, light stabilizers, plasticizers, surfactants, viscositymodifiers, compatibility agents, foaming agents, reinforcing agents,release agents, and the like.

Golf balls of the present invention optionally include one or moreintermediate layer(s) disposed between the core and the cover. Whenpresent, the overall thickness of the intermediate layer(s) is generallywithin the range having a lower limit of 0.01 inches or 0.05 inches or0.1 inches and an upper limit of 0.3 inches or 0.35 inches or 0.4inches. In addition to the rubber compositions of the present invention,suitable intermediate layer materials include, for example, naturalrubbers, balata, gutta-percha, cis-polybutadienes, trans-polybutadienes,synthetic polyisoprenes, polyoctenamers, styrene-propylene-dienerubbers, metallocene rubbers, styrene-butadiene rubbers,ethylene-propylenes, chloroprene rubbers, acrylonitrile rubbers,acrylonitrile-butadiene rubbers, styrene-ethylene block copolymers,maleic anhydride or succinate modified metallocene catalyzed ethylenecopolymers, polypropylene resins, ionomer resins, polyamides,polyesters, polyurethanes, polyureas, chlorinated polyethylenes,polysulfide rubbers, fluorocarbons, and combinations thereof.

Golf balls of the present invention preferably have an overall diameterwithin the range having a lower limit of 1.6 or 1.62 or 1.66 inches andan upper limit of 1.69 or 1.74 or 1.800 inches. More preferably, golfballs of the present invention have an overall diameter of 1.68 inches.Golf balls of the present invention preferably have a compression of 120or less, or 110 or less, or 105 or less. Golf balls of the presentinvention preferably have a COR at 125 ft/s of 0.750 or greater, or0.780 or greater, or 0.790 or greater, or 0.800 or greater.

Suitable golf ball constructions and materials are further disclosed,for example, in U.S. Patent Application Publication Nos. 2003/0144087,2005/0164810, and 2005/0255941; U.S. Pat. Nos. 5,688,119, 5,919,100, and7,004,856; and PCT Publications WO00/23519 and WO00/29129. The entiredisclosure of each of these references is hereby incorporated herein byreference.

In a particular embodiment, the present invention is directed to a golfball comprising a single layer core and a single-, dual-, or multi-layercover. The core layer is formed from a rubber composition comprising ahigh level of an oily substance and has a diameter of 1.4 inches orless. Preferably, the core has a diameter within the range having alower limit of 0.5 inches or 0.8 inches or 1.3 inches and an upper limitof 1.35 inches or 1.4 inches. The core layer preferably has acompression of 70 or less, or 60 or less, or 50 or less, or 45 or less.The cover preferably has an overall thickness of 0.1 inches or greater.The cover optionally includes an inner cover layer and an outer coverlayer, wherein the inner cover layer is formed from a highly resilientmaterial.

In another particular embodiment, the present invention is directed to agolf ball comprising a core, a polyurethane or polyurea outer coverlayer, and an intermediate layer disposed between the core and the outercover layer. The core layer is formed from a rubber compositioncomprising a high level of an oily substance and has a diameter of 1.4inches or less. Preferably, the core has a diameter within the rangehaving a lower limit of 0.5 inches or 0.8 inches or 1.3 inches and anupper limit of 1.35 inches or 1.4 inches. The core layer preferably hasa compression of 70 or less, or 60 or less, or 50 or less, or 45 orless. The intermediate layer has a thickness of 0.1 inches or greater,preferably from 0.1 inches to 0.3 inches, and is formed from a highlyresilient material. Suitable highly resilient materials include thehighly resilient materials disclosed above. Preferably the highlyresilient material of the intermediate layer is selected frompartially-neutralized acid copolymers, fully-neutralized acidcopolymers, blends of two or more partially-neutralized acid copolymers,blends of two or more fully-neutralized acid copolymers, and blends ofat least one partially-neutralized acid copolymer and at least onefully-neutralized acid copolymer.

In yet another particular embodiment, the present invention is directedto a golf ball comprising a 2-layer core and a 2-layer cover. The2-layer core includes an inner core layer (i.e., center) and an outercore layer. The inner core layer is formed from a rubber compositioncomprising a high level of an oily substance and preferably has adiameter of 1 inch. The outer core layer comprises a rubber compositioncomprising a base rubber and 5 parts or less of an oily substance, byweight per 100 parts of the base rubber, and preferably has a thicknessof 0.280 inches. Thus, the overall diameter of the 2-layer core ispreferably 1.560 inches. The 2-layer cover includes an inner cover layerand an outer cover layer. The inner cover layer comprises an ionomer andpreferably has a thickness of 0.030 inches. The outer cover layercomprises a castable polyurethane or polyurea composition and preferablyhas a thickness of 0.030 inches.

The present invention is not limited by any particular process forforming the golf ball layer(s). It should be understood that thelayer(s) can be formed by any suitable technique, including injectionmolding, compression molding, casting, and reaction injection molding.

For purposes of the present invention, compression is measured accordingto a known procedure, using an Atti compression test device, wherein apiston is used to compress a ball against a spring. The travel of thepiston is fixed and the deflection of the spring is measured. Themeasurement of the deflection of the spring does not begin with itscontact with the ball; rather, there is an offset of approximately thefirst 1.25 mm (0.05 inches) of the spring's deflection. Very lowstiffness cores will not cause the spring to deflect by more than 1.25mm and therefore have a zero compression measurement. The Atticompression tester is designed to measure objects having a diameter of42.7 mm (1.68 inches); thus, smaller objects, such as golf ball cores,must be shimmed to a total height of 42.7 mm to obtain an accuratereading.

For purposes of the present invention, COR is determined according to aknown procedure wherein a golf ball or golf ball subassembly (e.g., agolf ball core) is fired from an air cannon at a given velocity (125ft/s for purposes of the present invention). Ballistic light screens arelocated between the air cannon and the steel plate to measure ballvelocity. As the ball travels toward the steel plate, it activates eachlight screen, and the time at each light screen is measured. Thisprovides an incoming transit time period proportional to the ball'sincoming velocity. The ball impacts the steel plate and rebounds thoughthe light screens, which again measure the time period required totransit between the light screens. This provides an outgoing transittime period proportional to the ball's outgoing velocity. COR is thencalculated as the ratio of the outgoing transit time period to theincoming transit time period, COR=T_(out)/T_(in).

When numerical lower limits and numerical upper limits are set forthherein, it is contemplated that any combination of these values may beused.

All patents, publications, test procedures, and other references citedherein, including priority documents, are fully incorporated byreference to the extent such disclosure is not inconsistent with thisinvention and for all jurisdictions in which such incorporation ispermitted.

While the illustrative embodiments of the invention have been describedwith particularity, it will be understood that various othermodifications will be apparent to and can be readily made by those ofordinary skill in the art without departing from the spirit and scope ofthe invention. Accordingly, it is not intended that the scope of theclaims appended hereto be limited to the examples and descriptions setforth herein, but rather that the claims be construed as encompassingall of the features of patentable novelty which reside in the presentinvention, including all features which would be treated as equivalentsthereof by those of ordinary skill in the art to which the inventionpertains.

1. A solid golf ball comprising: a core having a diameter of 1.4 inchesor less and formed from a rubber composition comprising a base rubberand from 5 to 100 parts of an oily substance, by weight per 100 parts ofthe base rubber, a polyurethane or polyurea outer cover layer, and anintermediate layer disposed between the core and the outer cover layer,the intermediate layer having a thickness of 0.1 inches or greater andformed from a highly resilient material selected from partially- andfully-neutralized acid copolymers and blends thereof.
 2. The solid golfball of claim 1, wherein the core has a diameter of from 0.8 inches to1.4 inches and the intermediate layer has a thickness of from 0.1 inchesto 0.3 inches.
 3. The solid golf ball of claim 1, wherein the core has acompression of 50 or less.
 4. The solid golf ball of claim 1, whereinthe base rubber is selected from polybutadiene rubber, styrene-butadienerubber, and combinations of two or more thereof.
 5. The solid golf ballof claim 1, wherein the rubber composition comprises from 20 to 90 partsof the oily substance, by weight per 100 parts of the base rubber. 6.The solid golf ball of claim 1, wherein the oily substance is paraffinicoil.
 7. The solid golf ball of claim 1, wherein the rubber compositioncomprises 2.2 parts or greater of a cis-to-trans catalyst, by weight per100 parts of the base rubber.
 8. The solid golf ball of claim 1, whereinthe golf ball has a COR of 0.790 or greater.
 9. A solid golf ballcomprising: an inner core layer formed from a rubber compositioncomprising a base rubber and from 5 to 100 parts of an oily substance,by weight per 100 parts of the base rubber, and having a diameter of 1inch, an outer core layer formed from a rubber composition comprising abase rubber and 5 or less parts of an oily substance, by weight per 100parts of the base rubber, and having a thickness of 0.28 inches, aninner cover layer formed from a composition comprising an ionomer andhaving a thickness of 0.03 inches, and an outer cover layer formed froma composition comprising a castable polyurethane or polyurea and havinga thickness of 0.03 inches.